Conventional testing practices in the drum and pail container industry provide for assurance of leak-proof quality of container bodies, bottoms and head double seam. On the other hand, these known practices fail to enable examination of leak-proof quality in respect of the container head end where the testing involves the admission of pressurized air through a head end pour opening. In this omission, current testing practices fail in providing evidently desirable complete container quality data at the point of container manufacture. A still further disadvantage of known testing practices is their inability to provide continuity in monitoring container defects or quality deterioration occurring with passage of extended periods of time, e.g., the time extending from testing to use, or throughout shipment thereof to use.